This game is a Metroid parody starring a cat in a suit, exploring a weird space bio-research facility after its ship crashed.
Graphically it looks like an old-school (Game Boy/Spectrum/Commodore/Amstrad) game, with with modern smooth animation and controls. It's simple and monochromatic (black/white) but you can unlock color schemes (15 total) that give it a Spectrum/GB look, and many others. Monsters can be either cute or creepy, but the general visuals are really pleasant. The music is fairly old-school with XM/MOD sensibilities and fits the game like a glove.
While exploring, you must fight the various enemies, find save points, new gear for your mech-suit that unlocks new paths and access to secrets. You can exit your suit to crawl vents (and climb walls), swim, or even pilot a mini-attack sub. Exploring will also let you "read" logs which shed light on the overall plot of the game.
The boss fights are well-designed and will require use of all your arsenal and skills, and they're a genuinely great experience that helps maintain the dynamic pacing of the game.
Controls are mostly great, although sometimes it's a little slippery and aiming a jump can be a little tricky. because there is a lot of lateral acceleration, which makes some points a little frustrating, but never unfair or really hard. A controller is recommended for a comfortable experience, but keyboard is playable.
Be warned though, on Easy, if you're a "platform exploration" veteran (I hate the term Metroidvania), you can beat the game under 3 hours with almost 100%, and when fully upgraded the final boss is almost too easy. Also, like Metroid Fusion, the progression is essentially linear, with little reason to backtrack (except for secrets).
The short duration is the reason I only give it 4 stars, but on the other hand, it's a perfect introduction to the genre and a fun snack for people used to this type of game. Give it a chance, I bet you'll like it. I know I did.